Re: [Jts-topo-suite-user] JTS Overlay operation
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From: Martin D. <mtn...@gm...> - 2012-12-18 21:26:57
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Yes, the parentage-detemining problem is an issue. I've never been happy with the Point-in-Polygon approach, since it seems very susceptible to robustness problems, and isn't very efficient And of course it isn't helped by the "Interior Point on polygonal boundary" problem (which still needs to get fixed). In a proper overlay algorithm the parentage is maintained throughout noding and topology building, so it is fully determined when the output is produced. This is somewhat complex to code, however. if you spot any other documentation or FAQ issues I'm happy to hear about them! On Tue, Dec 18, 2012 at 12:54 PM, Michaël Michaud <mic...@fr...>wrote: > Hi, > > Ah, ok, that sounds like the classic "polygonal coverage overlay" problem. > The current JTS approach for this problem is here: > > http://tsusiatsoftware.net/jts/jts-faq/jts-faq.html#E3 > > Oh, yes. > I've followed this approach a couple of times (in OpenJUMP noder and in > OpenJUMP PlanarGraph plugin I think), > I found that determining the parentage is more difficult than it seems > because noding slightly change geometries and because I was relying on > Interior Point for the PIP test and at that time, InteriorPoint could be > on a > polygon boundary (don't remember if it is fixed). > > By the way, I'll read the FAQ before my next question ;-) > > |